Mac OS FAQ

Mac OS Disks

1. How do I partition and format disks in Mac OS?

When you first install Mac OS, it will create one (or more) partitions to install Mac OS. In Mac OS itself, you can use the Disk Utility to partition, repair, format, expand or shrink disks.

Here's an example dialog for resizing a partition:

Partition disk

2. I have Mac OS installed, but i need to reformat the system drive?

You cannot format the System partition while Mac OS is running. You need to boot into Recovery Mode by pressing Command + R and select the Disk Utility, alternatively you can boot from another bootable DVD or USB disc and use the Disk Utility to erase the partition. Select the Erase tab in Disk Utility, select the System Partition (the name may be different from image) and erase it. If you do not have bootable disc, try a GParted disc.

Erase a partition

3. How do I use the built in CD/DVD Burning software?

Mac OS has a built in CD/DVD burning engine installed. This will allow you to burn music, video or data to CDs. Then in an Finder window, you can select the files and folders you need to copy and copy them to the CD/DVD-R's drive. When you have copied all the files you need to copy, select File and Burn [disc name]'. To burn files/folders to multiple discs use Burn folders. For music, you can use iTunes to read/write music to/from CD. More info is available the Apple support pages.

4. I have added a new disk but it does not show in Finder?

You need to partition and give it a name before it will appear in Finder. Open Disk Utility and check that the disk is partitioned and formatted so that Mac OS can read it.
Also, the disk may be corrupt some how, so open Disk Utility and click on First Aid and click on Verify Disk to repair the disk. Alos, it may be worth verifying the Disk Permissions as well.

5. Can I backup my files to CD-R or DVD-R?

You can use free backup or burn tools to backup files to CD or DVD-R disks such as Burn, Toast or Aiseesoft DVD Creator etc

6. Which file system should I format my hard disk with?

You can use the Disk Utility to reformat drives in Mac OS, although this will lose data, unless backed up first. Mac OS supports multiple disk formats including:
* Mac OS Extended (Journalled) - Hierarchical Filing System, the default format used. It has Boot file, a Master Directory Block, Volume bitmap, Extent overflow file and a Catalog file.
* Mac OS Extended - Original format without the reliability of journaling
* Mac OS Extended (Case-sensitive, Journaled) - As above but uses a more Unix-like case-sensitive file system.
* MS-DOS (FAT) - Used for Bootcamp paritions and when sharing external drives with Windows users.

7. How do I change the disk to use MBR or GUID disks.

You can use the Disk Utility or gdisk command the in Mac OS to change the disk from MBR (Master Boot Record) to GPT (GUID Partition Table). See Partitions, Options in Disk Utility to change partition scheme. GPT has the advantage of supported disks larger than 2TB and unlimted number of partitions. Switching between types can be destructive, so backup your Mac first.

8. How can I create disk image files?

You can use the Disk Utility to create disk images. See File, New Image, Blank Image to create a disc image in four possible formats:
* Sparse bundle - Similar to sparse image but directory data for image stored differently.
* Sparse image - Creates an expandable file that shrinks and grows as needed.
* Read/write - Creates a DMG disk image, which allows you to add files after it is created.
* DVD/CD master - Creates a CDR disk image of 177 MB.

9. Can I play DVD or Blu-ray movies on my DVD or Blu-ray drive?

You can use the iTunes application to play CD or DVD discs, but for playing Blu-Ray discs you need third party applications such as Mac Go Blu-Ray Player.

Also, check your computer has upto date Graphics/Video drivers, a HD display with a DVI or HDMI connection, fast CPU and a Blu-Ray Player/Recorder device.